Q.1
Medium
What is the pH value of pure water at 25°C?
Explanation:
Pure water is neutral with a pH value of 7 at 25°C. Values below 7 are acidic and above 7 are basic.
Q.2
Medium
How many bones are there in the adult human body?
Explanation:
An adult human body has 206 bones. Infants are born with approximately 270 bones, many of which are cartilage.
Q.3
Medium
Which gas is primarily responsible for global warming?
A
Nitrogen
B
Oxygen
C
Carbon dioxide
D
Hydrogen
Correct Answer:
C. Carbon dioxide
Explanation:
Carbon dioxide (CO2) is the primary greenhouse gas responsible for global warming, released mainly through fossil fuel combustion.
Q.4
Medium
What is the SI unit of force?
A
Dyne
B
Newton
C
Joule
D
Pascal
Correct Answer:
B. Newton
Explanation:
Newton (N) is the SI unit of force. 1 Newton = 1 kg·m/s². Dyne is CGS unit, Joule is energy, Pascal is pressure.
Q.5
Medium
Which of the following is a conductor of electricity?
A
Rubber
B
Plastic
C
Copper
D
Ceramic
Correct Answer:
C. Copper
Explanation:
Copper is an excellent conductor of electricity due to free electrons. Rubber, plastic, and ceramic are insulators.
Q.6
Medium
The freezing point of water at standard atmospheric pressure is:
A
0°C
B
32°F
C
273.15 K
D
All of the above
Correct Answer:
D. All of the above
Explanation:
All three represent the same freezing point of water: 0°C, 32°F, and 273.15 K are equivalent.
Q.7
Medium
Which vitamin is produced by our skin when exposed to sunlight?
A
Vitamin A
B
Vitamin B
C
Vitamin C
D
Vitamin D
Correct Answer:
D. Vitamin D
Explanation:
Vitamin D is synthesized by our skin when exposed to ultraviolet-B (UVB) radiation from sunlight.
Q.8
Medium
What is the process by which water changes from liquid to gas?
A
Condensation
B
Sublimation
C
Evaporation
D
Freezing
Correct Answer:
C. Evaporation
Explanation:
Evaporation is the process where liquid water turns into water vapor/gas. This occurs at any temperature on the water's surface.
Q.9
Medium
Which of the following is a scalar quantity?
A
Velocity
B
Acceleration
C
Distance
D
Displacement
Correct Answer:
C. Distance
Explanation:
Distance is a scalar quantity as it has only magnitude. Velocity, acceleration, and displacement are vectors as they have both magnitude and direction.
Q.10
Medium
What is the process by which plants make their own food using sunlight?
A
Respiration
B
Photosynthesis
C
Fermentation
D
Decomposition
Correct Answer:
B. Photosynthesis
Explanation:
Photosynthesis is the process where plants convert sunlight, water, and carbon dioxide into glucose and oxygen.
